Conventional hole-processing methods used in fabricating circuit boards include mechanical drilling and injection molding. The mechanical drilling method cannot make small sized holes due to drilling tool limitations. Consequently, the holes will be easily seen and the circuit board cannot be waterproof. In addition, it is difficult to control the quality of the holes due to the vibration of the power drill during mechanical drilling operations.
Similarly, injection molding uses a mold with pins to define holes in the insulation substrate of a circuit board. To prevent the pins from collapsing because of the injection of insulation resin, the pins cannot be of a small size, and the injection molding technique cannot make holes of a small size as well. Consequently, the holes will be easily seen and the circuit board cannot be waterproof. In addition, the positions of the holes need to be confirmed and the mold needs to be manufactured first, and then the injection molding can be performed to manufacture the insulation substrate. As a result, the position and size of the holes cannot be easily changed.
This “Discussion of the Background” section is provided for background information only. The statements in this “Discussion of the Background” are not an admission that the subject matter disclosed in this “Discussion of the Background” section constitutes prior art to the present disclosure, and no part of this “Discussion of the Background” section may be used as an admission that any part of this application, including this “Discussion of the Background” section, constitutes prior art to the present disclosure.